Abstract: A simple, convenient method is provided for measuring the concentration of a constituent of an aqueous fluid composition (e.g. aqueous machining fluid composition) and for measuring total alkalinity thereof.

Abstract: The total alkalinity of an aqueous metalworking fluid is monitored and controlled by a continuous titration method that continuously supplies a stream of the metalworking fluid, at a known, controllable flow rate, to a flow through chamber having therein a static mixing element. Simultaneously and separately a stream of acid titrant, of known acid concentration is injected into the flow through chamber at a known controllable flow rate. The acid titrant and metalworking fluid mix and react in the chamber and the reacted metalworking fluid exiting the chamber passed over the tip of a pH electrode. The pH of the reacted metalworking fluid is continuously monitored and the output of the pH electrode used to adjust the flow of acid titrant to the chamber until an endpoint pH valve (typically a pH of 4) is reached.